[Media Router WebUI] Switch back to sink view after blocking issue is resolved.

[Media Router WebUI] Switch back to sink view after blocking issue is resolved.

When a blocking issue is resolved, container's |issue| is set to null. Currently, the UI doesn't switch back to the sink list view, leaving the user in a relatively blank issue view with no way of switching back.

Note that blocking issues take precedence to non-blocking issues, so there is no case where a blocking issue can be replaced by a non-blocking issue. It always becomes null when it is resolved.

This change also fixes an issue where the issue banner's offsetHeight is always 0.

BUG=601502
Review URL: https://codereview.chromium.org/1868983003

Cr-Commit-Position: refs/heads/master@{#387451}
(cherry picked from commit fee1baea9fdb05cb5867f46eb1ffe5c850be9d9c)

Committed: https://chromium.googlesource.com/chromium/src/+/f8eb1fe71cc1cd9506175970a2b933f32f374449

[apacible, 2016-04-18 21:21:14]

Description was changed from

==========
[Media Router WebUI] Switch back to sink view after blocking issue is resolved.

When a blocking issue is resolved, container's |issue| is set to null.
Currently, the UI doesn't switch back to the sink list view, leaving the user in
a relatively blank issue view with no way of switching back.

Note that blocking issues take precedence to non-blocking issues, so there is no
case where a blocking issue can be replaced by a non-blocking issue. It always
becomes null when it is resolved.

This change also fixes an issue where the issue banner's offsetHeight is always
0.

BUG=601502

Review URL: https://codereview.chromium.org/1868983003

Cr-Commit-Position: refs/heads/master@{#387451}
(cherry picked from commit fee1baea9fdb05cb5867f46eb1ffe5c850be9d9c)
==========

to

==========
[Media Router WebUI] Switch back to sink view after blocking issue is resolved.

When a blocking issue is resolved, container's |issue| is set to null.
Currently, the UI doesn't switch back to the sink list view, leaving the user in
a relatively blank issue view with no way of switching back.

Note that blocking issues take precedence to non-blocking issues, so there is no
case where a blocking issue can be replaced by a non-blocking issue. It always
becomes null when it is resolved.

This change also fixes an issue where the issue banner's offsetHeight is always
0.

BUG=601502

Review URL: https://codereview.chromium.org/1868983003

Cr-Commit-Position: refs/heads/master@{#387451}
(cherry picked from commit fee1baea9fdb05cb5867f46eb1ffe5c850be9d9c)

Committed:
https://chromium.googlesource.com/chromium/src/+/f8eb1fe71cc1cd9506175970a2b9...
==========

[apacible, 2016-04-18 21:21:15]

Committed patchset #1 (id:1) manually as
f8eb1fe71cc1cd9506175970a2b933f32f374449.